000 AXPZ20 KNHC 012136 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC TUE NOV 01 2011 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH IS ALONG 08N78W TO 10N85W TO 07N97W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N97W TO 08N115W TO 09N125W TO 08N140W. SCATTERED MODERATE CONVECTION IS WITHIN 90-120 NM N OF THE MONSOON TROUGH BETWEEN 85W AND 89W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 90-120 NM S OF THE ITCZ BETWEEN 126W AND 135W AND ALSO FROM 06N TO 11N W OF 136W. ...DISCUSSION... 1034 MB SURFACE HIGH PRES IS CENTERED WELL N OF THE AREA NEAR 42N132W ARCHING INTO THE AREA NEAR 32N138W TO 15N109W. A TIGHT PRES GRADIENT EXISTS OVER THE NW PORTION OF THE AREA AND A RECENT 1754 UTC ASCAT SCATTEROMETER PASS INDICATED FRESH NE-E WINDS ACROSS THE MAJORITY OF THE WATERS W OF 120W...EXCEPT E-SE FRESH WINDS S OF THE ITCZ. SHIP WITH CALL-SIGN PDAN NEAR 28N133W REPORTED NE 20 KT WINDS AT 2000 UTC. MIXED NE AND NW SWELL OF 8-11 FT COVERS THE AREA NW OF A LINE FROM 30N120W TO 20N140W AND A SHIP WITH CALL-SIGN VRZN7 NEAR 26N125W REPORTED 11 FT SEAS IN NE SWELL AT 1652 UTC. THE HIGH AND RIDGING WILL WEAKEN INTO WED AS A COLD FRONT MOVES FROM THE N CENTRAL PACIFIC INTO THE NE PACIFIC...ALLOWING THE WINDS TO DIMINISH IN INTENSITY AND AREAL EXTENT...WITH SWELL ALSO GRADUALLY SUBSIDING THROUGH 48 HOURS. MEANWHILE...THE CONVERGENCE OF THE FRESH TRADE WIND FLOW IS SUPPORTING MODEST CONVECTION ALONG THE ITCZ AS DESCRIBED ABOVE. AN UPPER LEVEL TROUGH IS EVIDENT IN WATER VAPOR SATELLITE IMAGERY FROM 24N120W TO 00N100W WITH VERY DRY AIR ACROSS THE AREA BETWEEN 95W AND 110W. AN UPPER LEVEL ANTICYCLONE IS OVER 18N91W WITH RIDGING EXTENDING S TO NEAR THE GALAPAGOS ISLANDS. 1008 MB SURFACE LOW PRES IS EMBEDDED IN THE MONSOON TROUGH NEAR 08N88W WITH ASSOCIATED CONVECTION AS DESCRIBED ABOVE BEING SUPPORTED ON THE E SIDE OF THE RIDGING. THE SURFACE LOW IS FORECAST TO MOVE TO NEAR 09N93W IN 24 HOURS WITH NO DEVELOPMENT ANTICIPATED. CROSS-EQUATORIAL SW SWELL TO 8 FT WITH PEAK WAVE PERIODS OF 17-19 SECONDS HAS BREACHED THE EQUATOR OVER THE FAR SE PORTION NE OF THE GALAPAGOS ISLANDS. THIS SWELL WILL SUBSIDE TO LESS THAN 8 FT WITHIN THE NEXT 24 HOURS...WITH A NEW SET OF SW SWELL ARRIVING OVER THE S CENTRAL WATERS IN 48 HOURS. GULF OF TEHUANTEPEC...A 1616 UTC ASCAT SCATTEROMETER PASS COVERED THE GULF OF TEHUANTEPEC REGION AND INDICATED MAINLY 20-25 KT WINDS WHILE LAND BASED STATION IXTEPEC IN THE MEXICAN STATE OF OAXACA REPORTED GUSTS TO 30 KT AT 17 UTC. A GALE WARNING IN THE GULF WILL BE ALLOWED TO EXPIRE AT 00 UTC BASED ON THIS DATA. THE NEXT STRONG COLD FRONT WILL MOVE BY TO THE N THROUGH THE SW GULF OF MEXICO LATE THU WITH ANOTHER SURGE OF COLD AND DENSE AIR EXPECTED TO FUNNEL THROUGH THE CHIVELA PASS AND DOWNWIND INTO THE GULF OF TEHUANTEPEC BEHIND THE FRONT. MODEL GUIDANCE TOPS WINDS OUT AT 30 KT AT THIS TIME ALTHOUGH WILL NEED TO CONTINUE TO MONITOR CONDITIONS AS WE GET CLOSER TO THE EVENT IN CASE ANOTHER GALE WARNING IS NEEDED. GULF OF CALIFORNIA...STRONG HIGH PRES WILL BUILD OVER THE UNITED STATES GREAT BASIN REGION BEHIND A COLD FRONT DURING THE NEXT 24 HOURS. STRONG NORTHERLY WINDS ARE FORECAST TO COMMENCE IN THE FAR NORTHERN GULF OF CALIFORNIA AROUND SUNRISE WED THEN WILL GRADUALLY DIMINISH AS THEY SPREAD SOUTHWARD THROUGH 48 HOURS. FINDINGS FROM A LOCAL RESEARCH STUDY WOULD INDICATE A HIGH LIKELIHOOD FOR GALE CONDITIONS IN THE FAR NORTHERN GULF WITH A VERY TIGHT PRES GRADIENT DEVELOPING OVER THE REGION BETWEEN THE HIGH AND TROUGHING E OF THE GULF OF CALIFORNIA. IF SUBSEQUENT MODEL RUNS CONTINUE TO INDICATE SUCH A TIGHT GRADIENT...A GALE WARNING WILL LIKELY BE NEEDED FROM 12 UTC WED THROUGH 00 UTC THU. $$ LEWITSKY